I have and always recommend steelcase chairs

Steelcase Leap - 2.5k~ ish.
Steelcase Think - 2k~ish

Price may change

I have sat extensively on both chair for long hours due to WFH. They are very comfortable and provide good support.
Material quality is awesome. I have the Leap for 2.5 years and it is still like new.

Your list of chairs were in my consideration.
So here are some of my comments:

1. Steelcase Leap
This one is around RM2.5K and above iirc. I didn't get to try but I didn't choose this model in the end because I didn't like the cushioned seat. I prefer mesh so it no longer in my list.

2. Merryfair Wau
I tested something similar to WAU, pretty sure it's the same manufacturer or OEM. (You can search for the shop called Arturo in Lazada to see they have a similar chair but more expensive for some reasons) I didn't like it myself, even though i'm 156CM and normal weight. I find it very small, for men or someone bigger surely you cannot fit into the chair.

3. AM Office POFIT
I tried and returned and refunded within 3 days. But had to make a huge noises about it because AMOFFICE after sales services are really horrible. POFIT does not have good quality for RM1,500 chair. I have more backaches after this chair. And also the app/digital/smart chair bullshits are just bullshits. They are horrible gimmicks and the app is really suspicious, asking for information & phone permissions that I really think they don't need at all. But there are also good reviews about this chair, so one's man poison may be another man's meat.

4. ErgoChair 2
Was also looking at this but didn't like that I had to pre-order at that point of time. And i didn't like that the backrest height couldn't be adjusted & cushioned seat. But otherwise i think the chair looks really good.

In the end I went to Evis and got myself ErgoPro with Legrest. xD

So ... in addition to the Merryfair Spinelly (posted about this earlier), I also just added a Merryfair Wau 2 for my wife.
Here are my thoughts on the chairs you are looking at.

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1. Steelcase Leap V2
This is much more comfortable and build quality is much better than the Merryfairs. However, just like @miyakochan89 pointed out, the promo package for the Leap V2 (RM2.5k) is only with the cushion back rest, but I prefer a mesh one. There is no promo package for the mesh backrest, so you will have to pay full price ( > RM4k). More importantly, the sales people at ZenPro are damn f**king LCLY, and put me off buying anything from them.

Note: I also tested the Steelcase Think which is (no promo) about RM2.2k for one ... comfort is quite decent but the headrest cannot pakai one. However, they did tell me that the headrest will be upgraded for 2021 models.
2. Merryfair Wau
As mentioned above, I bought this already. A lot of adjustability with very good lumbar support, but build quality is very "plasticky" ... does not feel high end at all. My pregnant wife is very happy with it though. The good thing about buying from Merryfair is you can customize everything, including colour and material.
3. AM Office POFIT
I actually found this really comfortable ... first impressions were excellent. But build quality is also very "plasticky", similar to my feedback on the Merryfair above.

Note: I also tested the Ergohuman which was nicely built (compared to the POFIT), but somehow I just couldn't find the right fit for me (I think this is more to do with my own body than a fault of the chair).
4. ErgoChair 2
No comments - did not test

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Overall, I am happy with my Merryfair Spinnelly and Wau, which with the promo price, both added up still cost less than one Steelcase Leap (even with their promo). Like I said, the Steelcase is a better chair, but there are some compromises you have to make unless you don't mind paying full price. More importantly, customer service at Merryfair is top notch compared to those at ZenPro.

Sekian, terima kasih.